CN216074037U - Protective layer structure of zinc-coated cadmium alloy of aluminum alloy part - Google Patents
Protective layer structure of zinc-coated cadmium alloy of aluminum alloy part Download PDFInfo
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Abstract
The utility model discloses a protective layer structure of a zinc-cadmium alloy plated on an aluminum alloy piece, which comprises an aluminum alloy matrix, and a zinc deposition layer, a pre-copper plating layer, a zinc-cadmium alloy plating layer, a trivalent chromium passivation layer and a silane passivation layer which are sequentially prepared on the aluminum metal matrix from inside to outside. The utility model has the advantages that: the preparation process is environment-friendly, and the prepared plating layer has high corrosion resistance.
Description
Technical Field
The utility model relates to the field of metal electroplating, in particular to a protective layer structure of zinc-plated cadmium alloy of an aluminum alloy piece.
Background
At present, the high-corrosion-resistance plating layers prepared by aerospace enterprises comprise cadmium plating layers and cadmium-titanium alloy plating layers, and the plating layers are subjected to post-treatment by adopting a high-toxicity hexavalent chromium passivation process.
Disclosure of Invention
The utility model aims to provide a protective layer structure of a zinc-cadmium alloy of an aluminum alloy piece, which aims to solve the problem of high pollution caused by passivation of hexavalent chromium in cadmium plating and alloys thereof of aerospace enterprises.
In order to achieve the purpose, the utility model adopts the following technical scheme:
a protective layer structure of a zinc-plated cadmium alloy of an aluminum alloy piece comprises an aluminum alloy matrix, and a zinc deposition layer, a pre-copper plating layer, a zinc-cadmium alloy plating layer, a trivalent chromium passivation layer and a silane passivation layer which are sequentially prepared on the aluminum alloy matrix from inside to outside;
the zinc-cadmium alloy plating layer is prepared by adopting a potassium chloride zinc-cadmium alloy electroplating process;
the silane passivation layer is prepared by adopting a solvent type silane chromium-free passivation process.
In some embodiments, the thickness of the zinc-cadmium alloy coating is 8-24 μm.
In some embodiments, the thickness of the pre-plated copper layer is 3-13 μm.
In some of these embodiments, the thickness of the silane passivation layer is 0.7-1.3 μm.
Compared with the prior art, the utility model has the beneficial effects that:
1. the zinc-cadmium alloy plating layer disclosed by the utility model has excellent corrosion resistance and is suitable for preparing high-corrosion-resistance plating layers in various strong corrosion environments;
2. according to the utility model, the trivalent chromium passivation layer and the silane passivation layer are prepared on the zinc-cadmium alloy coating, so that the problem of high pollution of the traditional hexavalent chromium passivation can be solved, the silane passivation layer is further formed on the trivalent chromium passivation layer, and the silane passivation layer has self-repairability and can overcome the technical defect that the trivalent chromium passivation layer does not have self-repairability;
3. according to the utility model, the pre-plated copper layer is prepared on the zinc-deposited layer containing two metals by adopting an HEDP copper plating process, HEDP complex copper ions cannot replace zinc on the zinc-deposited layer, and good bonding force can be formed between the two plating layers;
4. the zinc-cadmium alloy plating layer belongs to a cathode plating layer relative to an aluminum alloy substrate, and the plating layer has no electrochemical protection effect on the substrate.
Drawings
The accompanying drawings, which are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the utility model and together with the description serve to explain the principles of the utility model:
fig. 1 is a schematic structural diagram of protective layers in examples 1 and 2 of the present invention.
Detailed Description
The present invention will be described in detail with reference to the drawings and specific embodiments, which are illustrative of the present invention and are not to be construed as limiting the present invention.
A protective layer structure of a zinc-cadmium alloy plated on an aluminum alloy piece comprises an aluminum alloy base body, and a zinc deposition layer, a pre-copper plating layer, a zinc-cadmium alloy plating layer, a trivalent chromium passivation layer and a silane passivation layer which are sequentially prepared on the aluminum alloy base body from inside to outside.
The aluminum alloy part is subjected to wax removal, oil removal and activation by adopting the conventional pretreatment process.
After the pretreatment of the aluminum alloy part, the zinc deposition layer is prepared by adopting the existing chemical zinc deposition process.
Preferably, the zinc deposition layer is prepared by adopting AZIN-113 acidic aluminum zinc deposition agent produced by Guangzhou ultra-Pont chemical Co., Ltd: 50-250 mL/L of AZIN-113 acidic aluminum zinc deposition agent, working temperature of 15-30 ℃, zinc deposition liquid pH range of 3.4-4.2, and zinc deposition time of 20-80 s. The prepared zinc deposition layer contains two components of zinc and nickel.
Preferably, the zinc deposition layer is prepared by adopting an ALBUME AS-699 cyanide-free aluminum zinc deposition agent produced by ultra-high chemical industry: 160-200 mL/L of ALBUME AS-699 cyanide-free aluminum zinc-plating agent, the working temperature is 20-30 ℃, and the zinc-plating time is 60-120 s. The prepared zinc deposition layer contains two components of zinc and copper.
After the chemical zinc deposition of the aluminum alloy part, preparing the pre-plated copper layer by adopting an HEDP copper plating process, wherein the thickness of the prepared plating layer is 3-13 mu m.
The HEDP copper plating process comprises the following steps: 35-45 g/L of copper sulfate, 80-130 g/L of HEDP complexing agent, 40-60 g/L of potassium carbonate, 20-25 mL/L of CuR-1 additive, pH range of 9-10, plating bath temperature of 35-50 ℃, and cathode current density of 1-3A/dm2The cathode is moved for 2-4 m/min.
The zinc-cadmium alloy coating is prepared by adopting a potassium chloride zinc-cadmium alloy electroplating process developed by ultra-high chemical industry, and the thickness of the coating is 8-24 mu m.
The electroplating process of the potassium chloride zinc cadmium alloy comprises the following steps: 30-50 g/L of zinc chloride, 10-25 g/L of cadmium chloride, 100-160 g/L of coordination agent, 1.5-2.5 mL/L of brightening agent, 25-35 mL/L of auxiliary agent, 6.5-7.5 of pH, 15-35 ℃ of plating bath temperature and 0.5-2.5A/dm of cathode current density2The mass fraction of metal and zinc contained in the zinc anode plate is more than or equal to 99.99%, the mass fraction of metal and cadmium contained in the cadmium anode plate is more than or equal to 99.97%, and the area ratio of the zinc anode plate to the cadmium anode plate is 5: 1-2.
The complexing agent in the process comprises a component A and a component B, wherein the component A comprises nitrilotriacetic acid and glycine, the mass ratio of the nitrilotriacetic acid to the glycine is 7: 4-6, the component B comprises any one or two of citric acid, tartaric acid, gluconic acid and malic acid, and the ratio of the component A to the component B is 7: 6-10.
The brightener in the process comprises C, D, E, F, G five components, wherein the component C is alpha-vinyl-N-propyl sulfonic pyridine inner salt (CAS NO.6613-64-5), the component D is o-chlorobenzaldehyde, the component E comprises any one or two of 3-methoxy-4-hydroxybenzaldehyde, 3, 4-dimethoxybenzaldehyde and 4-methoxybenzaldehyde, the component F comprises any one or two of propargyl alcohol ethoxy ether, propargyl alcohol propoxy ether, N-diethyl propargylamine, N-diethyl propargylamine formate, N-diethyl propargylamine sulfate and propinyl salt, and the component G is butyl ether salt, and is prepared according to the following proportion and method: uniformly mixing 200mL of deionized water and 400mL of isopropanol, adding 30-60G of the component C, 20-30G of the component D, 30-50G of the component E, 100-150G of the component F and 40-70G of the component G, stirring until all the components are completely dissolved, and adding water to 1000 mL;
the auxiliary agents in the process comprise polyacrylamide with small molecular weight, sodium benzoate, sodium dimethyl benzene sulfonate and a condensation compound consisting of ethylenediamine and epichlorohydrin, and the auxiliary agents are prepared according to the following proportion and method: adding 50-80 g of low-molecular-weight polyacrylamide, 30-60 g of sodium benzoate, 50-80 g of sodium dimethyl benzene sulfonate, 30-70 g of a condensation compound of ethylenediamine and epichlorohydrin into 600g of water, stirring to dissolve the condensation compound, and adding water to 1000 mL.
The trivalent chromium passivation layer is prepared by adopting the existing trivalent chromium passivation process.
Preferably, the trivalent chromium passivation layer is prepared by adopting a TRIROS TYP-168 trivalent chromium color passivation process in the ultra-high chemical industry: 100-130 mL/L TRIROS TYP-168 concentrated solution, 2-6 mL/L TRIROS TYP-168B additive, pH of 1.7-2.3, temperature of 25-70 ℃, soaking time of 30-90 s, and stirring in air.
The method comprises the steps of preparing a silane passivation layer after electroplating zinc-nickel alloy on an aluminum alloy part, wherein the silane passivation layer is prepared by using a zinc Cuctite PRODICOZ-Caot 888FL chromium-free passivator in super-bonding chemical industry, and the thickness of the passivation layer is 0.7-1.3 mu m.
The passivation process comprises the following steps: the zinc can be special PRODICOZ-Caot 888FL is a solvent type, the raw solution is used, the operation is carried out at room temperature, the passivation time is 30-90 s, and the baking is carried out for 18-25 min at the temperature of 80-100 ℃.
Example 1:
as shown in fig. 1, the protective layer structure of the zinc-cadmium alloy plated on the aluminum alloy piece comprises an aluminum alloy substrate 1, and a zinc deposition layer 2, a pre-copper plating layer 3, a zinc-cadmium alloy plating layer 4, a trivalent chromium passivation layer 5 and a silane passivation layer 6 which are sequentially prepared on the aluminum alloy substrate 1 from inside to outside.
The zinc deposition layer 2 is prepared by adopting AZIN-113 acid aluminum zinc deposition agent produced by ultra-high chemical industry: 150mL/L of AZIN-113 acidic aluminum zinc deposition agent, 25 ℃ of working temperature, 3.8 of pH of zinc deposition liquid and 50s of zinc deposition time. The prepared zinc deposition layer contains two components of zinc and nickel.
The pre-plated copper layer 3 is prepared by an HEDP copper plating process, and the thickness of the plating layer is 8-10 mu m.
The HEDP copper plating process comprises the following steps: 37g/L of copper sulfate, 90g/L of HEDP complexing agent, 45g/L of potassium carbonate, CuR-1 additive of 20mL/L, pH range of 9, plating bath temperature of 40 ℃, and cathode current density of 1.8A/dm2The cathode was moved 3 m/min.
The thickness of the zinc-cadmium alloy coating 4 is 10-12 mu m, and the zinc-cadmium alloy coating is prepared by adopting a potassium chloride zinc-cadmium alloy electroplating process developed by ultra-high chemical industry.
The electroplating process of the potassium chloride zinc cadmium alloy comprises the following steps: 40g/L of zinc chloride, 18g/L of cadmium chloride, 130g/L of coordination agent, 2.0mL/L of brightening agent, 30mL/L of auxiliary agent, pH of 7.0, plating bath temperature of 25 ℃, and cathode current density of 1.5A/dm2The mass fraction of metal and zinc contained in the zinc anode plate is more than or equal to 99.99%, the mass fraction of metal and cadmium contained in the cadmium anode plate is more than or equal to 99.97%, and the area ratio of the zinc anode plate to the cadmium anode plate is 5: 1.5.
The complexing agent in the process comprises two components A and B, wherein the component A comprises nitrilotriacetic acid and glycine, the mass ratio of the nitrilotriacetic acid to the glycine is 7: 5, the component B comprises any one or two of citric acid, tartaric acid, gluconic acid and malic acid, and the ratio of the component A to the component B is 7: 8.
The brightener in the process comprises C, D, E, F, G five components, wherein the component C is alpha-vinyl-N-propyl sulfonic pyridine inner salt (CAS NO.6613-64-5), the component D is o-chlorobenzaldehyde, the component E comprises any one or two of 3-methoxy-4-hydroxybenzaldehyde, 3, 4-dimethoxybenzaldehyde and 4-methoxybenzaldehyde, the component F comprises any one or two of propargyl alcohol ethoxy ether, propargyl alcohol propoxy ether, N-diethyl propargylamine, N-diethyl propargylamine formate, N-diethyl propargylamine sulfate and propinyl salt, and the component G is butyl ether salt, and is prepared according to the following proportion and method: uniformly mixing 200mL of deionized water and 400mL of isopropanol, adding 45G of the component C, 25G of the component D, 40G of the component E, 130G of the component F and 60G of the component G, stirring until all the components are completely dissolved, and adding water to 1000 mL;
the auxiliary agents in the process comprise polyacrylamide with small molecular weight, sodium benzoate, sodium dimethyl benzene sulfonate and a condensation compound consisting of ethylenediamine and epichlorohydrin, and the auxiliary agents are prepared according to the following proportion and method: 60g of low-molecular-weight polyacrylamide, 40g of sodium benzoate, 60g of sodium dimethyl benzene sulfonate, 50g of ethylenediamine and epichlorohydrin condensate are added into 600g of water and stirred to be dissolved, and then water is added to 1000 mL.
The trivalent chromium passivation layer 5 is prepared by adopting a TRIROS TYP-168 trivalent chromium color passivation process in the ultra-high chemical industry: 120mL/L TRIROS TYP-168 concentrated solution, 5mL/L TRIROS TYP-168B additive, pH of 2.1, temperature of 50 ℃, soaking time of 40s, and stirring in air.
The silane passivation layer 6 is prepared from a zinc Cuachable PRODICOZ-Caot 888FL chromium-free passivator in the super-bonding chemical industry, and the thickness of the passivation layer is 1.0-1.2 mu m.
The passivation process comprises the following steps: the zinc can be prepared into solvent type PRODICOZ-Caot 888FL, using as stock solution, operating at room temperature, inactivating for 50s, and baking at 85 deg.C for 25 min.
The operation of the embodiment is divided into the following steps:
1. pretreatment: the aluminum alloy workpiece base 1 is subjected to the steps of "chemical wax removal → water washing → ultrasonic wax removal → water washing → chemical degreasing → water washing → activation → water washing".
2. Chemical zinc deposition: the pretreated aluminum alloy workpiece substrate 1 is subjected to the procedures of 'first zinc deposition → water washing → zinc removal → water washing → second zinc deposition → water washing' to prepare the zinc deposition layer 2.
3. Pre-copper plating: and preparing a pre-plated copper layer 3 on the zinc deposition layer 2 according to the HEDP copper plating process.
4. Electroplating zinc-cadmium alloy: the zinc-cadmium alloy plating layer 4 is prepared on the pre-plated copper 3 by a potassium chloride zinc-cadmium alloy electroplating process.
5. Passivation of trivalent chromium: and (3) performing ' nitric acid light extraction with volume fraction of 1% ' washing → trivalent chromium color passivation → washing → drying ' on the zinc-cadmium alloy coating 4 to prepare a trivalent chromium passivation layer 5.
6. Chromium-free passivation: and (3) preparing a silane passivation layer 6 by performing silane passivation on the trivalent chromium passivation layer 5 → tapping a groove → blowing off liquid drops remained at the bottom of the workpiece by high-pressure air → drying and curing.
Example 2:
as shown in fig. 1, the protective layer structure of the zinc-cadmium alloy plated on the aluminum alloy piece comprises an aluminum alloy substrate 1, and a zinc deposition layer 2, a pre-copper plating layer 3, a zinc-cadmium alloy plating layer 4, a trivalent chromium passivation layer 5 and a silane passivation layer 6 which are sequentially prepared on the aluminum alloy substrate 1 from inside to outside.
The zinc deposition layer 2 is prepared by adopting an ALBUME AS-699 cyanide-free aluminum zinc deposition agent produced by ultra-high chemical industry: 180mL/L of ALBUME AS-699 cyanide-free aluminum zinc deposition agent, 25 ℃ of working temperature and 80s of zinc deposition time. The prepared zinc deposition layer contains two components of zinc and copper.
The pre-plated copper layer 3 is prepared by an HEDP copper plating process, and the thickness of the plating layer is 10-12 mu m.
The HEDP copper plating process comprises the following steps: 43g/L copper sulfate, 120g/L HEDP complexing agent, 55g/L potassium carbonate, 25mL/L CuR-1 additive, pH range of 10, plating bath temperature of 45 ℃, and cathode current density of 2.5A/dm2The cathode was moved 3 m/min.
The thickness of the zinc-cadmium alloy coating 4 is 12-14 mu m, and the zinc-cadmium alloy coating is prepared by adopting a potassium chloride zinc-cadmium alloy electroplating process developed by ultra-high chemical industry.
The electroplating process of the potassium chloride zinc cadmium alloy comprises the following steps: 45g/L of zinc chloride, 20g/L of cadmium chloride, 140g/L of complexing agent, 2.0mL/L of brightener, 30mL/L of auxiliary agent, 6.8 of pH, 30 ℃ of plating bath temperature and 2.0A/dm of cathode current density2The mass fraction of metal and zinc contained in the zinc anode plate is more than or equal to 99.99%, the mass fraction of metal and cadmium contained in the cadmium anode plate is more than or equal to 99.97%, and the area ratio of the zinc anode plate to the cadmium anode plate is 5: 1.5.
The complexing agent, brightener and auxiliary agent described in the process are the same as in example 1.
The trivalent chromium passivation layer is prepared by adopting a TRIROS TYP-168 trivalent chromium color passivation process in the super-nation chemical industry: the TRIROS TYP-168 concentrated solution is 110mL/L, the TRIROS TYP-168B additive is 4mL/L, the pH is 1.9, the temperature is 50 ℃, the immersion time is 35s, and the air stirring is carried out.
The silane passivation layer is prepared from a zinc Cuctite PRODICOZ-Caot 888FL chromium-free passivator in the super-bonding chemical industry, and the thickness of the passivation layer is 0.8-1.0 mu m.
The passivation process comprises the following steps: the zinc can be prepared into solvent type PRODICOZ-Caot 888FL, using stock solution, operating at room temperature, inactivating for 70s, and baking at 95 deg.C for 20 min.
The operation of the embodiment is divided into the following steps:
1. pretreatment: the aluminum alloy workpiece base 1 is subjected to the steps of "chemical wax removal → water washing → ultrasonic wax removal → water washing → chemical degreasing → water washing → activation → water washing".
2. Chemical zinc deposition: the pretreated aluminum alloy workpiece substrate 1 is subjected to the procedures of 'first zinc deposition → water washing → zinc removal → water washing → second zinc deposition → water washing' to prepare the zinc deposition layer 2.
3. Pre-copper plating: and preparing a pre-plated copper layer 3 on the zinc deposition layer 2 according to the HEDP copper plating process.
4. Electroplating zinc-cadmium alloy: preparing a zinc-cadmium alloy coating 4 on the pre-plated copper 3 according to a potassium chloride zinc-cadmium alloy electroplating process.
5. Passivation of trivalent chromium: and (3) performing ' nitric acid light extraction with volume fraction of 1% ' washing → trivalent chromium color passivation → washing → drying ' on the zinc-cadmium alloy coating 4 to prepare a trivalent chromium passivation layer 5.
6. Chromium-free passivation: and (3) preparing a silane passivation layer 6 by performing silane passivation on the trivalent chromium passivation layer 5 → tapping a groove → blowing off liquid drops remained at the bottom of the workpiece by high-pressure air → drying and curing.
Test example 1:
the protective layers prepared in examples 1 and 2 were tested for the adhesion between the coating and the coating by the thermal shock test method in accordance with JB 2111-1977 method for testing the adhesion strength of metallic coatings. And (3) heating the plated part in a heating furnace to 190 ℃, taking out the plated part after 30min, placing the plated part in water at room temperature, and cooling the plated part suddenly, wherein the protective layer does not generate bubbles or fall off.
The protective layers prepared in the embodiment 1 and the embodiment 2 are subjected to a neutral salt spray test for 2000h according to GB/T10125-.
The technical solutions provided by the embodiments of the present invention are described in detail above, and the principles and embodiments of the present invention are explained herein by using specific examples, and the descriptions of the embodiments are only used to help understanding the principles of the embodiments of the present invention; meanwhile, for a person skilled in the art, the specific implementation and the application range can be changed according to the embodiment of the present invention. In general, nothing in this specification should be construed as limiting the utility model.
Claims (4)
1. A protective layer structure of a zinc-cadmium alloy plated on an aluminum alloy piece is characterized by comprising an aluminum alloy matrix, and a zinc deposition layer, a pre-copper plating layer, a zinc-cadmium alloy plating layer, a trivalent chromium passivation layer and a silane passivation layer which are sequentially prepared on the aluminum alloy matrix from inside to outside;
the zinc-cadmium alloy plating layer is prepared by adopting a potassium chloride zinc-cadmium alloy electroplating process;
the silane passivation layer is prepared by adopting a solvent type silane chromium-free passivation process.
2. The protective layer structure of the zinc-cadmium alloy of the aluminum alloy part according to claim 1, wherein the thickness of the zinc-cadmium alloy coating is 8-24 μm.
3. The protective layer structure of the aluminum alloy piece of the zinc-coated cadmium alloy according to claim 1, wherein the thickness of the pre-copper plating layer is 3 to 13 μm.
4. The protective layer structure of the aluminum alloy piece zinc-coated cadmium alloy according to claim 1, wherein the thickness of the silane passivation layer is 0.7-1.3 μm.
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